Abstract
| Original language | English |
|---|---|
| Journal | Journal of Solid State Chemistry |
| Volume | 211 |
| Pages (from-to) | 81-89 |
| ISSN | 0022-4596 |
| DOIs | |
| Publication status | Published - 2014 |
Keywords
- Lithium borohydride
- Calcium borohydride
- Calcium hydride
- Solid electrolyte
- Ionic conductivity
- X-ray diffraction
Cite this
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Ionic conductivity and the formation of cubic CaH2 in the LiBH4-Ca(BH4)2 composite. / Sveinbjörnsson, Dadi Þorsteinn; Blanchard, Didier; Mýrdal, Jón Steinar Garðarsson; Younesi, Reza; Viskinde, Rasmus; Riktor, Marit Dalseth; Norby, Poul; Vegge, Tejs.
In: Journal of Solid State Chemistry, Vol. 211, 2014, p. 81-89.Research output: Contribution to journal › Journal article › Research › peer-review
TY - JOUR
T1 - Ionic conductivity and the formation of cubic CaH2 in the LiBH4-Ca(BH4)2 composite
AU - Sveinbjörnsson, Dadi Þorsteinn
AU - Blanchard, Didier
AU - Mýrdal, Jón Steinar Garðarsson
AU - Younesi, Reza
AU - Viskinde, Rasmus
AU - Riktor, Marit Dalseth
AU - Norby, Poul
AU - Vegge, Tejs
PY - 2014
Y1 - 2014
N2 - LiBH4–Ca(BH4)2 composites were prepared by ball milling. Their crystal structures and phase composition were investigated using synchrotron X-ray diffraction and Rietveld refinement, and their ionic conductivity was measured using impedance spectroscopy. The materials were found to form a physical mixture. The composites were composed of α-Ca(BH4)2, γ-Ca(BH4)2 and orthorhombic LiBH4, and the relative phase quantities of the Ca(BH4)2 polymorphs varied significantly with LiBH4 content. The formation of small amounts of orthorhombic CaH2 and cubic CaH2 in a CaF2-like structure was observed upon heat treatment. Concurrent formation of elemental boron may also occur. The ionic conductivity of the composites was measured using impedance spectroscopy, and was found to be lower than that of ball milled LiBH4. Electronic band structure calculations indicate that cubic CaH2 with hydrogen defects is electronically conducting. Its formation along with the possible precipitation of boron therefore has an effect on the measured conductivity of the LiBH4–Ca(BH4)2 composites and may increase the risk of an internal short-circuit in the cells.
AB - LiBH4–Ca(BH4)2 composites were prepared by ball milling. Their crystal structures and phase composition were investigated using synchrotron X-ray diffraction and Rietveld refinement, and their ionic conductivity was measured using impedance spectroscopy. The materials were found to form a physical mixture. The composites were composed of α-Ca(BH4)2, γ-Ca(BH4)2 and orthorhombic LiBH4, and the relative phase quantities of the Ca(BH4)2 polymorphs varied significantly with LiBH4 content. The formation of small amounts of orthorhombic CaH2 and cubic CaH2 in a CaF2-like structure was observed upon heat treatment. Concurrent formation of elemental boron may also occur. The ionic conductivity of the composites was measured using impedance spectroscopy, and was found to be lower than that of ball milled LiBH4. Electronic band structure calculations indicate that cubic CaH2 with hydrogen defects is electronically conducting. Its formation along with the possible precipitation of boron therefore has an effect on the measured conductivity of the LiBH4–Ca(BH4)2 composites and may increase the risk of an internal short-circuit in the cells.
KW - Lithium borohydride
KW - Calcium borohydride
KW - Calcium hydride
KW - Solid electrolyte
KW - Ionic conductivity
KW - X-ray diffraction
U2 - 10.1016/j.jssc.2013.12.006
DO - 10.1016/j.jssc.2013.12.006
M3 - Journal article
VL - 211
SP - 81
EP - 89
JO - Journal of Solid State Chemistry
JF - Journal of Solid State Chemistry
SN - 0022-4596
ER -